1. Field of the Invention
The invention relates to glassy alloys and, in particular, to glassy alloys in the Fe-Cr-Mo-B system evidencing ultra-high strengths.
2. Description of the Prior Art
High strength alloys in filamentary form are required as reinforcement for composites. Filaments of crystalline alloys have traditionally provided sufficient strength in composites. However, new engineering materials requiring even higher strengths than heretofore provided are necessary. More recently, glassy alloys, such as disclosed in Chen et al., U.S. Pat. No. 3,856,513, have evidenced high ultimate tensile strengths of 500 Kpsi and greater.
Masumoto et al. in U.S. Pat. No. 3,986,867 disclose a number of iron-chromium base glassy alloys. These alloys are disclosed as having excellent mechanical properties, corrosion resistance and heat resistance. Among iron-chromium-boron glassy alloys in which the range of boron is 15 to 20 atom percent, ultimate tensile strengths of 370 to 440 Kpsi are disclosed. For glassy alloys in the Fe-Cr-Mo-P-C-B system in which the boron content is 5 atom percent, ultimate tensile strengths of 480 to 580 Kpsi are disclosed. For glassy alloys in the Fe-Cr-P-C-B system in which the boron content ranges from 25 to 30 atom percent, ultimate tensile strengths of about 525 kpsi are disclosed. However, it is also known that the presence of phosphorus degrades the thermal stability of glassy alloys; see, e.g., Luborsky et al., Journal of Applied Physics, 47, 3648-50 (1976) and Polk et al., U.S. Pat. No. 4,052,201, issued Oct. 4, 1977. The crystallization temperature of the phosphorus-containing alloys of Masumoto et al. is typically about 370.degree. to 515.degree. C.